The U.S. Department of Energy (DOE) has created a number of useful new resources to help stakeholders understand IES TM-30-15, which describes a new method for evaluating light-source color rendition.

Created by an Illuminating Engineering Society (IES) task group to address the widely acknowledged limitations of CRI, which is simpler to use but less accurate, TM-30 encompasses several individual measures and graphics that complement one another and, together, provide a comprehensive characterization of how the light will affect the color appearance of objects.

TM-30 uses 99 color samples that come in all hues, both saturated and unsaturated, and were chosen to cover the range found in common consumer goods and natural objects. The three highest-level components of TM-30 are the Fidelity Index (Rf), the Gamut Index (Rg), and the Color Vector Graphic. Numerous sub-indices can provide more-detailed information about such things as the color fidelity of reds, the chroma shift of reds, and the fidelity of skin tones.

The new DOE resources on TM-30 include: 

  • A fact sheet, “Evaluating Color Rendition Using IES TM-30-15”
  • A video featuring Michael Royer of Pacific Northwest National Laboratory, who chaired the IES TM-30 task group
  • An extensive list of FAQs on TM-30, featuring the answers to 65 questions related to its development, measures, application, and data.